Per default the login ui of the default organization is shown.
To allow users of a specific organization to register with their IDP (e.g Entra ID) you have two options.

1. Identify organization with organization scope

By sending the organization scope in the authorization request to ZITADEL the specified organization will directly be triggered.
The configured settings of that organization such as IDPs will directly be shown.
If only one IDP is configured and local accounts are disabled the user will directly be redirected to the external provider.
```
urn:zitadel:iam:org:id:{id}
```

2. Domain Discovery

When domain discovery is enabled, ZITADEL is able to identify the entered domain of a user and match it to a specific organization.
If you want to know more about domain discovery and how to set it up please read the following guide:
[Domain Discovery in ZITADEL](/docs/guides/solution-scenarios/domain-discovery)
